Case IH 19789 – Engine Control Module (ECM) or Dosing Control Unit (DCU) / Supply Module: SCR Inducement: Warning, triggered by DEF/AdBlue dosing interruption fault

Indicates that the Selective Catalytic Reduction (SCR) system has detected a physical or electrical interruption in the delivery of Diesel Exhaust Fluid (DEF) / AdBlue into the exhaust stream. This triggers an inducement warning and will escalate to Level 1 (Torque reduction) and Level 3 (Creep mode/severe power loss) if unresolved.

• Tier 4b
• 240 Series Axial-Flow
• 7240
• 8240
• 9240
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 110A
• Farmall 115U
• Farmall 120A
• Farmall 130A
• Farmall 140A
• Puma 150
• Maxxum 115
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Steiger 435
• Patriot 2250
• Patriot 3240
• Patriot 3340
• Farmlift 632
• Farmlift 635
• Farmlift 735
• Farmlift 742
• Farmlift 935

1. 1

   Verify battery and alternator are supplying proper voltage to the ECM and DEF modules (low voltage is a common cause)

2. 2

   Inspect the DEF tank unit assembly and suction tube for cracks that could cause the pump to draw air and lose prime

3. 3

   Check the DEF/AdBlue dosing valve actuator circuit for secondary codes indicating a short circuit to the battery or ground

4. 4

   Inspect the DEF filter for severe blockages or crystallization restricting fluid flow

5. 5

   Use a diagnostic scan tool to run an AdBlue/DEF dosing valve control test to verify pump pressure (up to 9 bar/130 psi) and check for nozzle blockages

1. 1

   Scan and Verify

   Connect a diagnostic tool to read all active codes. If secondary electrical codes (e.g., short circuits) are present for the dosing valve, address the wiring harness or replace the valve first.

2. 2

   Resolve Suction Leaks

   If the system builds pressure initially but drops off when the machine moves, remove the DEF tank unit assembly. Pressurize the suction tube slightly to check for hairline cracks. If cracked, replace the tank unit assembly.

3. 3

   Replace the DEF Filter

   If the fluid is contaminated or the filter is old, replace the DEF filter cartridge and clean the housing.

4. 4

   Replace the Dosing Valve/Injector

   If the dosing valve is electrically failed or physically blocked by crystallized DEF (and cannot be cleared), remove the V-band clamp at the exhaust pipe, disconnect the heated DEF line and electrical connector, and install a new dosing valve.

5. 5

   Replace the DEF Pump (Supply Module)

   If the pump motor has failed, has an internal heater failure, or cannot maintain pressure despite a sealed suction line, replace the DEF pump module. Note: A new DEF pump module will require programming/calibration to the vehicle's ECM using a dealer scan tool after installation.

6. 6

   Clear and Test

   Clear the 19789 fault code and perform a forced DEF dosing test to ensure the system primes, builds pressure, and injects fluid without interruption.